1. Potassium iodide   AgCl   NaOH   ZnS   KI   Hint Hint       2. Sodium iodide   NaI   ZnS   NaCl   HCl   Hint       3. Sodium chloride   KOH   NaCl   KI   AgBr   Hint       4. Calcium oxide   NaOH   CaO   MgS   AgCl   Hint       5. Sodium hydroxide   NaOH   HCl   KI   NaCl   Hint       6. Potassium hydroxide   HgO   KOH   KI   NaCl   Hint       7. Potassium chloride   KBr   CuO   KCl   HgO   Hint